Epilating machine and control circuit



April 25, 1967 A. w. DONELSON EPILATING MACHINE AND CONTROL CIRCUIT 5Sheets-Sheet l Filed July 17, 1964 ATTORNEYS APYi 25, 1967 A. W.DoNELsoN 3,315,678

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ARTHUR W. DONLSON BY ATTORNEYS i April 25, 1967 A. W. DONELSON 3,315,678

EPILATING MACHINE AND CONTROL CIRCUIT Filed July l?, 1964 5 Sheets-Sheet5 CLA MP VIS' ../.sm/ INVENTOR ARTHUR W. DONELSON. BY

@mmmwgumm ATTORNEYS United States Patent() 3,315,678 EPILATING MACHINEAND CONTROL CIRCUIT Arthur W. Donelson, Fiint, Mich., assigner toEpilation, Inc., Detroit, Mich. Filed .iuiy 17, 1964, Ser. No. 383,31811 Claims. (Cl. 12S-303.18)

This invention relates to an epilating machine and more particularly toan automatic intermittently operable quick acting control circuitincluding a power supply wherein the said circuit is actuated by anamplified very small voltage differential from the human body achievedon application of the probe to the pore of a human body.

It is an object of the present invention to provide a control circuitfor an epilating machine which utilizes the electrical potentialdifferential between the human body and said machine, and uses thissmall potential difference as the control mechanism for `activating theepilating machine.

It is a further object to take this small voltage impulse, amplify thesame in the present control circuit to operate triggering mechanismswhich in turn control the momentary and temporary release of radiofrequency energy to the probe for a momentary burning operation in thedestruction of a hair follicle.

It is another object to provide an epilating device which is painless tothe user and which employs high intensity radio frequency energy.

These and other objects and advantages will be seen from the followingspecifications and claims in conjunction with the appended drawings inwhich:

FIG. 1 is a schematic block diagram of the present epilating machineindicating the power supply, the radio frequency power supply and thecontrol circuit connected with the power supply for deliveringintermittent radio frequency energy to the probe.

FIG. 2 is a fragmentary land schematic wiring diagram showing theconnections of the probe to the RF source and to the audio amplifier inthe control circuit and with details as to filter and audio amplifier ofFIG. l.

FIG. 3 is a similar diagram showing the connection of the amplifier ofFIG. 2 to the V6 thyraton with remote control, connected speaker andcathode follower of FIG. 1.

lFIG. 4 is a similar diagram showing the connections from the cathodefollower of FIG. 3 to the Schmitt trigger V8 of FIG. 1, connectedthyraton V9 and cathode follower V7B.

FIG. 5 is a similar diagram corresponding to FIG. 1 showing theconnection between the cathode follower V7B of FIG. 4 and the Schmitttrigger V10 and connected neon lamps.

FIG. 6 is a schematic wiring diagram showing the wiring betwen the neonlamps of FIG. 5 and clamp tube V13 and screen grids of V1 and V2 for thepower amplifier controlled thereby.

It will be understood that the above drawings illustrate merely apreferred embodiment of the invention and a simplified schematic versionof the wiring to the extent required for an explanation of the functionand operation of the present control circuit for the epilating machine.

R.F. POWER SOURCE Referring to the drawings, in FIG. l, the needle probeof the epilating machine is schematically shown by box 11 and whichreceives through filter 14 and coaxial cable 13 intermittent shortduration radio frequency energy from the conventional RF power amplifier12 which includes a pair of control tubes V1-V2. Said power amplifierincludes a standard pi network, to deliver radio frequency energythrough filter 14 to probe 11 and has a preselected setting, forillustration, of 27.120 mc. approved Patented Apr. 25, 1967 ICC undertype #ME-5 69 from the Federal Communications Commission.

. Box V4 is suitably connected to the power supply 22 which includes aswitch and a voltage regulator and receives 150 volts D.C., forillustration, from said power supply. V4 is a crystal controlled triodeoscillator which is adjustable; and in the illustrative embodiment hasbeen set at 27.120 megacycles which is delivered at approximately sixvolts, for illustration, to the RF driver amplifier V3, in turndelivering volts to RF power amplifier 12, which includes control tubesV1 and V2.

Thus, the present epilating machine includes needle probe 11, an RFsource with an RF power amplifier 12 with control tubes V1 and V2 andcoaxial cable 13 which interconnects the amplifier, the tubes and theprobe.

AUTOMATIC CONTROL CIRCUIT The present invention is directed to anautomatic intermittently operable quick acting control circuit whichincludes power supply 22 with voltage regulator, which power supply isadapted to deliver through its various leads the required current andvoltages or biases to the said circuit as hereafter described. Forexample, it delivers 700 volts D.C. through lead 23, volts through lead24, 375 volts D.C. through lead 25, 6.3 volt-s A C. through lead 26,minus l5 volts through lead 27, all as schematically shown in FIG. l.

Many of the elements in the control circuit are conventional elementswhich may be purchased on the market and it is therefore the combinationof these elements which makes up the present control circuit for theepilating machine.

VS is an audio amplifier with gain control, FIG. l, and shown in detailin FIG. 2. It is connected in series to the normally non-conductivethyraton tube V6 which has a remote control designated by box 17 and theletter C5, C8. V6 activates speaker 18 through a suitable transformer,FIG. 3. Remote control 17 is also connected to a second thyratron tubeV9, in turn also connected to said transformer.

Thyratron V6 is connected to cathode follower V7A in turn connected withSchmitt trigger V8 which incorporates Zener diode 28, FIG. 4.

FIG. 3 illustrates in detail the connections between thyratron V6,cathode follower V7A, remote control 17, transformer T2 and speaker 18.

Schmitt trigger V8 connects a second thyratron V9 which through cathodefollower V7B is connected to a second Schmitt trigger V10, FIG. l.Thyratron V9 has a switch 20 for manual control of the control circuit.

Schmitt trigger V141 is connected through a series of neon tubes 19 toclamp tube V13, which is normally conductive (and-tubes V1-V2inoperative) and which has a warm-up time delay unit 21. Tube V13 isconnected to control grids V1-V2 of the RF power amplier12, FIG. 6.

OPERATION Audio amplifier Referring to FIGS. 1 and 2, a very smallvoltage or potential differential is applied by the human body to probe11 and through lead 16 is directed to the resistance coupled audioamplifier V5 which includes tubes VSA and VSB.

This voltage is passed by resistance R1 and R2 to the grid of VSA. R1and R2 together with condensers C1 and C2 function as a resistancecapacitance filter designated at 14, FIG. 1, and serves to prevent RFvoltage from the output RF amplifier 12 from damaging VSA.

An amplified version of this small voltage which VSA grid receives, FIG.2, appears at the plate of VSA and the alternating current component ispassed through condenser C3 to potentiometer R3 where any portion ofthis voltage may be selected and impressed upon the grid of VSB tube.This further amplifies the initial small voltage, which appears asamplified on the plate of VSB and is passed through condenser C4 to thegrid of normally non-conductive thyratron tube V6, FIG. 3.

R4 serves to maintain the grid voltage of V5A constant. R5 and R6 serveto bias the grids of VSA and VSB respectively by maintaining theircathodes positive in relation to their grids. VSA and VSB tubes may thusbe referred to as a resistance coupled audio amplifier with gaincontrol.

T liyratron tube When the voltage impressed on the grid of thyratron V6,FIG. 3, exceeds a certain value, as for example 3 volts, V6 thyratronbecomes conductive. That is to say: electrons flow from the cathode tothe plate charging C5 condenser. R7 of FIG. 3, serves to hold the normalgrid voltage of V6 thyratron at minus l5 volts, which is required tohold this tube in a normally non-conductive condition.

Any current which ypasses through V6 thyratron and the second thyratronV9, FIGS. l and 4, passes through the T2 primary, FIG. 3, includingacurrent in the secondary of T2 and producing a characteristic click atthe connected speaker 1S.

Thyratron remote control V6 thyratron ceases to conduct when the voltagedifferential between its plate and cathode reach a certain minimumvalue. This leaves condenser C5 with a charge which now biases V6 tohigh value, preventing it from again becoming conductive until the C5charge is reduced by the current now caused to flow through R8potentiometer.

This requires an interval of time, adjustable by the variable arm of R8.Potentiometer R8 and associated condenser C5 thus form the remotecontrol 17, FIG. l. Said time interval over which the charge isgradually reduced in condenser C5 is regulated by potentiometer R8, FIG.3.

` Cathode follower Schmitt trigger The cathode of V7A follower conductsthis timed voltage through R11, FIG. 3, to the input grid of tube V8,FIG. 4, which is connected as a Schmitt trigger.

The circuit in FIG. 4 with reference to Schmitt trigger V8 is soadjusted that the right triode is normally conducting and the lefttriode is cut-off by the voltage drop in R12 connected with Zener diode28.

When the input grid of V8 is carried positive the left triode suddenlybecomes conductive and the right triode non-conductive. As the voltageat the input grid of the left triode becomes less as the charge incondenser C5 dissipates, as in FIG. 3, this condition again suddenlyreverses, being a characteristic of the Schmitt trigger. When thisoccurs, the voltage drop across R13 becomes zero, the voltage at theplate of the left triode snaps positive to the voltage of the powersupply, causing a positive pulse to pass through C6 condenser, FIG. 4.

Zener diode 28, FIG. 4, is in series with R12 to cause the circuit toproduce this pulse before C5, FIG. 3, has lost all of its charge, andtherefore shortly before V6 thyratron is capable of again becomingconductive.

Second thyratron tube and cathode follower The pulse of voltage from C6condenser, FIG. 4, is connected to the grid of V9 thyratron, which isidentical in performance to thyratron V6 except that condenser C8 in itscathode circuit has less capacity.

Thyratron V9 also has a cathode follower V7B for isolation which isdirectly coupled to the input grid of a second Schmitt trigger V16, FIG.5.

Second Schmitt trigger Here the Schmitt trigger functions as a switch.The left triode is normally at cut-off, and the right triode is normallyconducting. The plate current of the left triode rises `sharply when theinput grid becomes positive and remains so until the C8 condenser ofthyratron V9 is nearly discharged, whereupon it returns to normal. Therise of plate current of V10 Schmitt trigger of the left tube causes adrop in voltage in R14, FIG. 5, which, through the neon lamps 19 allowthe bias to increase on the grid of clamp tube V13 which then cuts off,FIG. 6.

The neon tubes have a nearly constant voltage across them ofapproximately 250 Volts when current passes through them.

Clamp tube The clamp tube V13, FIG. 6, normally conducts sufficientcurrent to reduce the voltage on its plate and hence, the screen gridsof V1-V2 of RF power amplifier 12 to a low value, thereby causing V1 andV2 to be inoperative when clamp tube V13 is conductive. However, whenV13 cuts off its plate current the screen grids of V1-V2 now rise to thenormal operating voltage for such period of time as determined bycondenser C3 of thyratron V9.

RF power ampler V1 and V2, FIGS. l and 6, comprise a conventional poweramplifier 12 with a standard pi network, to deliver a certain radiofrequency energy, as for example, 27.120 mc. through connections 13 andfilter 14 to probe 11. The filter is large enough to pass the RF energyto the probe but small enough in capacity so as not to by-pass thevoltage required by V5 audio amplifier.

The RF energy is passed through filter 14, FIG. 2, and is conveyed tothe needle probe via coaxial cable 13' which is tuned to exactlyone-half wave at a preselected operating frequency 27.120 mc. forillustration. This results in delivering the useful energy to theepilator needle or probe 11 at the lowest possible impedance for minimumdiscomfort to the patient.

The V1-V2 tubes, FIG. 6, comprise a conventional RF power amplifier 12with a pi network for delivering RF energy through filter C7.

The primary purpose of the present circuit is to provide a painlessdevice. This is achieved by using an application of such highintensity-radio frequency energy as to be able to epilate duringextremely short period of carefully controlled time. This probably doesnot give the nerves time to respond to such short stimulus.

Having described my invention reference should now be had to thefollowing claims.

I claim:

1. In an epilatingy machine, a needle probe, an RF source with an RFpower amplifier including control tubes having screen grids, and acoaxial cable interconnecting the amplifier tubes and probe; theinvention comprising;

an automatic intermittently operable quick acting control circuitincluding a power supply and voltage regulator;

an audio amplifier with gain control in said circuit connected to saidprobe amplifying the small voltage received by the probe when itcontacts the human body;

a normally non-conductive thyratron tube connected to the audioamplifier intermittently rendered conductive by said amplified voltagefor delivering a timed voltage; Y

a normally non-conductive-Schmitt trigger connected to the thyratron fordelivering an intermittent voltage pulse upon termination of the timedvoltage from said thyratron;

and a normally conductive clamp tube interconnected between said Schmitttrigger and the screen grids of said RF power amplifier and including acontrol grid connected to said Schmitt trigger, current flow in thetubes of the power amplifier being normally cut-off;

said voltage pulse from the Schmitt trigger to the clamp tube gridcutting off ow through said clamp tube to intermittently activate thecontrol tubes of said RF power amplifier, to deliver through saidcoaxial cable a momentary surge of RF power to said probe.

2. In the epilating machine of claim 1, an adjustable timing means forholding the thyratron non-conductive after a fall of voltage from saidaudio amplifier, consisting of a condenser in parallel circuit with theoutput of said thyratron which builds up a charge during flow of currentfrom said thyratron to the Schmitt trigger, and wherein aftertermination of said flow biases the thyratron to a high valuetemporarily preventing it from becoming conductive;

and a grounded remote manually controlled variable resistance connectedacross said condenser conducting current therefrom reducing its chargeover a controllable interval, said interval being determined byadjustment of said resistance.

3. In the epilating machine of claim 1, said thyratron including a plateenergized when the thyratron is momentarily conductive; and

an audio speaker with transformer connected with said plate producing anaudible click at the moment the thyratron is rendered conductive.

4. In the epilating machine of claim 1, and a resistance capacitancefilter in said circuit at the junction of said coaxial cable, probe andaudio amplifier for transmitting RF energy to the probe but of a smallenough capacity to preclude by-passing damaging RF voltage to said audioamplifier.

5. In the epilating machine of claim 1, said coaxial cable being tunedto exactly one-half wave at a predetermined operating RF frequency forthe momentary delivery of useful RF energy to said probe at the lowestpossible impedance for minimum discomfort to the patient.

6. In the epilating machine of claim 1, an adjustable timing means forholding the thyratron non-conductive after a fall of voltage from saidaudio amplifier, consisting of:

a condenser in parallel circuit with the output of said thyratron whichbuilds up a charge during fiow of current from said thyratron to theSchmitt trigger, and wherein after termination of said ow biases thethyratron to a high value temporarily preventing it from becomingconductive;

and a grounded remote manually controlled variable resistance connectedacross said condenser conduct- -ing current therefrom reducing itscharge over a controllable interval, said interval being determined byadjustment of said resistance; and

a cathode follower in the circuit between said thyratron and Schmitttrigger duplicating the rise and fall of the charge in said condenserduring the time interval of its gradual discharge and corresponding tothe period when the thyratron is maintained nonconductive by saidcharge.

7. In the epilating machine of claim 1, and a series of neon tubes insaid circuit interposed between said Schmitt trigger and clamp tube formaintaining when energized aV substantially constant voltage.

8. In the epilating machine of claim 1, an adjustable timing means forholding the thyratron non-conductive after a fall of voltage from saidaudio amplifier, consisting of;

a condenser in parallel circuit with the output of said thyratron whichbuilds up a charge during ow of current from said thyratron to theSchmitt trigger, and wherein after termination of said flow biases thethyratron to a high value temporarily preventing it from becomingconductive;

a. grounded remote manually controlled variable resistance connected inparallel with said condenser conducting current therefrom reducing itscharge over a controllable interval, said interval being determined byadjustment of said resistance;

and a Zener diode connected to said Schmitt trigger effecting said pulseof the Schmitt trigger before said condenser has lost all of its chargeand before said thyratron is capable of again becoming conductive.

9. In the epilating machine of claim 1, a second normally non-conductivethyratron delivering a second timed voltage in less time than said firstthyratron, and switch means developing a second voltage pulse inresponse to said second timed voltage interposed between said Schmitttrigger and clamp tube to deliver said second voltage pulse to saidclamp tube grid.

10. In the epilating machine of claim 1, a second normallynon-conductive thyratron developing a second timed voltage in less timethan said first thyratron interposed between said Schmitt trigger andclamp tube;

and a second normally non-conductive Schmitt trigger interposed betweensaid second thyratron and said clamp tube and functioning as a switchdelivering voltage to said clamp tube in response to said second timedvoltage biasing the latters grid until said second thyratron is nearlydischarged.

11. In the epilating machine of claim 1, a second normallynon-conductive thyratron developing a second timed voltage in less timethan said first thyratron interposed between said Schmitt trigger andclamp tube;

a second normally non-conductive Schmitt trigger interposed between saidsecond thyratron and said clamp tube and functioning as a switchdelivering Voltage to said clamp tube in response to said second timedvoltage biasing the latters grid until said second thyratron is nearlydischarged;

and a cathode follower interposed between said second thyratron and saidsecond Schmitt trigger.

References Cited bythe Examiner UNITED STATES PATENTS 2,827,056 3/ 1958Degelman 12S-422 FOREIGN PATENTS 897,961 6/ 1962 Great Britain.

OTHER REFERENCES 1,139,927, November 1962, Germany. 1,146,989, April1963, Germany.

RICHARD A. GAUDET, Primary Examiner. W. E. KAMM, Assistant Examiner.

1. IN AN EPILATING MACHINE, A NEEDLE PROBE, AN RF SOURCE WITH AN RFPOWER AMPLIFIER INCLUDING CONTROL TUBES HAVING SCREEN GRIDS, AND ACOAXIAL CABLE INTERCONNECTING THE AMPLIFIER TUBES AND PROBE; THEINVENTION COMPRISING; AN AUTOMATIC INTERMITTENTLY OPERABLE QUICK ACTINGCONTROL CIRCUIT INCLUDING A POWER SUPPLY AND VOLTAGE REGULATOR; AN AUDIOAMPLIFIER WITH GAIN CONTROL IN SAID CIRCUIT CONNECTED TO SAID PROBEAMPLIFYING THE SMALL VOLTAGE RECEIVED BY THE PROBE WHEN IT CONTACTS THEHUMAN BODY; A NORMALLY NON-CONDUCTIVE THYRATRON TUBE CONNECTED TO THEAUDIO AMPLIFIER INTERMITTENTLY RENDERED CONDUCTIVE BY SAID AMPLIFIEDVOLTAGE FOR DELIVERING A TIMED VOLTAGE; A NORMALLY NON-CONDUCTIVESCHMITT TRIGGER CONNECTED TO THE THYRATRON FOR DELIVERING ANINTERMITTENT VOLTAGE PULSE UPON TERMINATION OF THE TIMED VOLTAGE FROMSAID THYRATRON; AND A NORMALLY CONDUCTIVE CLAMP TUBE INTERCONNECTEDBETWEEN SAID SCHMITT TRIGGER AND THE SCREEN GRIDS OF SAID RF POOERAMPLIFIER AND INCLUDING A CONTROL GRID CONNECTED TO SAID SCHMITTTRIGGER, CURRENT FLOW IN THE TUBES OF THE POWER AMPLIFIER BEING NORMALLYCUT-OFF; SAID VOLTAGE PULSE FROM THE SCHMITT TRIGGER TO THE CLAMP TUBEGRID CUTTING OFF FLOW THROUGH SAID CLAMP TUBE TO INTERMITTENTLY ACTIVATETHE CONTROL TUBES OF SAID RF POWER AMPLIFIER, TO DELIVER THROUGH SAIDCOAXIAL CABLE A MOMENTARY SURGE OF RF POWER TO SAID PROBE.